By way of example, collimators are used for imaging using X-ray equipment such as a computed tomography scanner in order to examine a patient. The computed tomography scanner has an X-ray system with an X-ray source and an X-ray detector arranged on a gantry. The X-ray detector is generally constructed from a multiplicity of detector modules which are arranged in an adjoining linear or two-dimensional fashion. Each detector module of the X-ray detector for example comprises a scintillator array and a photodiode array which are aligned with respect to one another. The mutually aligned elements of the scintillator array and of the photodiode array form the detector elements of the detector module. The X-ray radiation incident on the scintillator array is converted into light which is converted into electrical signals by the photodiode array. The electrical signals form the starting point for the reconstruction of an image of an object or patient examined using the computed tomography equipment.
The X-ray radiation emanating from the X-ray source is scattered in the object and so scattered beams, so-called secondary beams, are incident on the X-ray detector in addition to the primary beams from the X-ray source. These scattered beams cause noise in the X-ray image and therefore reduce the perceptibility of the contrast differences in the X-ray image. In order to reduce the influence of scattered radiation, an X-ray absorbing collimator is arranged over every scintillator array, as a result of which collimator only X-ray radiation from a certain spatial direction reaches the scintillator array.
Until now, it was mainly collimators comprising a number of tungsten sheets which were used in medical technology for use in a computed tomography scanner. Collimators which permit suppression of scattered radiation in the φ-direction only, that is to say in the rotation direction of the gantry, comprise a multiplicity of collimator sheets which are arranged in parallel and are aligned with respect to the X-ray focus; these are referred to as one-dimensional collimators. If the X-ray detector is enlarged in the Z-direction, that is to say in the direction of the patient axis, two-dimensional collimation is also required in the Z-direction. Such a two-dimensional collimator is described, for example, in U.S. Pat. No. 7,362,894 B2, the entire contents of which are hereby incorporated herein by reference. In this case, as the detector becomes wider, it becomes evermore difficult to produce the grid-like support mechanism with sufficient accuracy in order to keep the sheets in position.